ABSTRACT
Ocular tonometry is a class of NI measurement that allows an ophthalmologist to estimate the internal hydraulic pressure of the eyeballs, called the intraocular pressure (IOP). The IOP is the result of the constant production of the liquid aqueous humor (AH) into the interior of the eyes. The AH is found around the lens and in the anterior chamber of the eye. It serves as a nutrient solution for the lens, the iris, and the inside of the cornea, and its pressure helps to maintain the proper shape of the eyeball. The simplest, most inaccurate, and subjective means of estimating IOP is by digital manipulation of the cornea through the closed eyelid. The ideal, invasive means of measuring IOP would be to penetrate the eyeball with a saline-filled, hypodermic needle and cannula connected to a pressure sensor. All contact tonometers require sterile technique and anesthetization of the corneal surface.
